My husband works in adoption work. Whenever the state is involved (at least in Colorado) and they are dealing with a Mormon, it is a big deal that the child is not fed "food storage." It is considered dangerous. I always laugh at that, but I guess if we are storing food we should know when it becomes dangerous....when is it better to just discard food. Here are some signs.
1. Bulging lid can be signs of trouble.
2. Milky appearance to liquid.
3. Mold growth of any kind.
4. Slimy appearance and texture
5. Rancid odor
6. Corrosion on inside of can.
8. Frozen can or bottle. If it was frozen, you can use it immediately when it defrosts, but once it has thawed, the food will begin to spoil.
9. Off smell.
That being said, the cans and dry items that we buy at the store have an expiration date that is for the ideal quality. Most items will last for two years.
Utah State University Food Extension